The present invention relates to a compound concrete composition for the manufacture of moulds intended in particular for moulding articles made of plastic.
Metallised concrete moulds have been proposed to make articles made of plastic more economical to mould, in particular those of large size, such as body components for motor vehicles.
The compound concretes which form part of the constitution of these moulds must combine different properties. Firstly, they must ensure good thermal conductivity, since these moulds are heated and/or cooled during the moulding operation.
Secondly, they must have mechanical properties which ensure good ductility and a satisfactory flexural strength, since the moulds are subjected to a considerable mechanical stress when they are being employed.
Finally, they must have a suitable expansion coefficient which is compatible with that of the metal coating of the mould and possibly with that of metal components which are needed for the moulding and at least a part of which is embedded in the concrete.